Various inkjet printing arrangements include both thermally actuated printheads and mechanically actuated printheads. Thermal actuated printheads tend to use resistive elements or the like to achieve ink expulsion, while mechanically actuated printheads tend to use piezoelectric transducers or the like.
A representative thermal inkjet printhead has a plurality of thin film resistors provided on a semiconductor substrate. A barrier layer is deposited over thin film layers on the substrate. The barrier layer defines firing chambers about each of the resistors, an orifice corresponding to each firing chamber, and an entrance or fluid channel to each firing chamber. Often, ink is provided through a slot in the substrate and flows through the fluid channel to the firing chamber. Actuation of a heater resistor by a “fire signal” causes ink in the corresponding firing chamber to be heated and expelled through the corresponding orifice.
In some instances, bubbles or particles can occlude fluid flow through the fluid slot, through the fluid channel, or within the firing chamber. Print quality and resistor life may be affected by the fluid occlusion. Accordingly, there is a desire to maximize tolerance to bubbles and/or particles within the fluid ejection device.